The 7.6-magnitude quake was "one of the strongest earthquakes" ever to hit the Central American nation, President Laura Chinchilla said.

The president praised residents' response, saying there were no reports of major physical damage from the quake.

"Costa Ricans knew how to react," she said.

The quake struck Costa Rica's Nicoya Peninsula Wednesday morning, on the Pacific coast about 87 miles west of the capital, San Jose. It was centered more than 28 miles deep.

Schools in the hardest hit areas will be closed Thursday and Friday while engineers inspect buildings for damage, Chinchilla said.

Officials gave conflicting reports about whether anyone had been killed.

Late Wednesday Chinchilla said there were "no human losses," but earlier emergency officials said at least one person had died from a heart attack suffered during the quake.

"It started out pretty mild, but then it really got going," said Bill Root, owner of a hotel in Samara, also near the epicenter. "It was a very strong earthquake. Everything was falling off the shelves and the ground was rolling."

Costa Rica's National Emergency Commission reported debris on roads, electrical outages and some structural damage in homes, especially on the Nicoya Peninsula, about 14 kilometers (8 miles) from the epicenter.

Red Cross ambulances evacuated patients from two damaged hospitals, said Enrique Guevara, a spokesman for the Red Cross in the Americas.

Hours after the quake, authorities canceled all tsunami warnings and watches.

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CNN affiliate Teletica showed people streaming out of buildings when the earthquake hit.

Telephone service was knocked out in cities near the epicenter, Teletica reported. The station showed photos submitted by viewers of a partially collapsed bridge over the Rio Sucio and a landslide on a highway. Other photos showed floors littered with merchandise inside stores and homes with minor damages.

"It's unnerving when solid concrete beneath you is shaking from side to side. It was pretty scary," said David Boddinger, editor of the English-language Tico Times in San Jose.

Seismologists have been predicting a strong quake in that area for years now, and Costa Ricans were wondering if this was the big one, he said.